Protein Similarities in the Genus Tetrahymena and a Description of Tetrahymena leucophrys n. sp.1

Abstract
The potential utility of protein arrays visualized by SDS‐PAGE in taxonomic studies of protozoa has been investigated within the genus Tetrahymena. Matching coefficients have been obtained from one‐dimensional separations of cytoskeletal proteins in a study involving 40 strains of Tetrahymena. In separate studies, the method was estimated to be accurate to within 10%, and the limit of intraspecific variation within the genus was estimated at ≅ 30%. Accordingly, it is suggested that strains showing matching coefficients 0.6 in these preparations probably represent different species. Further tests using strains identified to species by breeding criteria have shown that the 0.6 rule is asymmetric, i.e. although matching coefficients lower than this indicate separate species, values higher than this do not prove identity. Protein comparisons included in the present study indicate that strain Tur, previously identified as a strain of T. vorax, is distinct from all other macrostome‐forming species. It is here designated Tetrahymena leucophrys n. sp.